A117803 Triangular numbers for which the sum of the digits is a cube.
0, 1, 10, 5778, 5886, 6786, 7875, 17766, 17955, 27495, 29646, 31878, 36585, 38781, 43956, 46665, 46971, 49455, 49770, 55278, 58653, 61776, 64980, 68265, 74691, 75078, 78606, 85491, 85905, 89253, 93096, 93528, 97461, 109278, 109746, 117855
Offset: 1
Examples
5778 is in the sequence because (1) it is a triangular number and (2) the sum of its digits 5+7+7+8=27 is a cube.
Links
- Harvey P. Dale, Table of n, a(n) for n = 1..1000
Programs
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Mathematica
Select[Accumulate[Range[500]],IntegerQ[Power[Total[IntegerDigits[#]], (3)^-1]]&] (* Harvey P. Dale, Dec 19 2010 *) Select[Accumulate[Range[0,500]],IntegerQ[Surd[Total[IntegerDigits[#]],3]]&] (* Harvey P. Dale, Jan 08 2023 *)
Extensions
Corrected by Harvey P. Dale, Jan 08 2023